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2018 Vol.37, Issue 1
Estimation of a transition point of sound propagation condition using transmission loss data measured in SAVEX15

SAVEX15 실험 해역에서 측정된 전달손실 자료를 이용한 음파 전달 조건의 변환점 추정

Hyuckjong Kwon1
,
Jee Woong Choi1*
,
Byoung-Nam Kim2
권 혁종1
,
최 지웅1*
,
김 병남2
1Department of Marine Science and Convergence Engineering, Hanyang University
1한양대학교 해양융합공학과 해양음향공학연구실
2한국해양과학기술원
*교신저자. *Corresponding Author. 
31 January 2018. pp. 1-11
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Abstract

Sound propagation in shallow water changes from spherical spreading to cylindrical spreading, depending on boundary conditions, and this point is defined as a transition point of the sound propagation condition. Theoretically, the transition point can be estimated using the transmission loss as a function of source-receiver range. In this paper, the transmission loss curve in a Pekeris waveguide is predicted using a parabolic-equation based acoustic propagation model and using this transmission loss curve, the range from the source of the transition point is estimated, which is compared to the critical distance calculated using the sound speed ratio of water to sediment. In addition, the effects of the sound speed profile and source depth change on the transition point are investigated. Finally, the transition point is estimated using the transmission loss data measured during the period of the SAVEX15 (Shallow Water Acoustic Variability EXperiment 2015) conducted 65 km southwest of Jeju Island in May 2015, and it is compared to the ocean environmental parameters to understand the properties of sound propagation in the experimental area.

Keywords
Sound propagation
Transmission loss
Transition point
Spherical spreading
Cylindrical spreading

천해 환경에서 음파 전달은 경계면에 의해 구형 분산에서 원통형 분산으로 음파 전달 조건이 전환되는데, 이 지점을 음파 전달 조건의 변환점 (transition point)이라고 정의한다. 이론적으로 거리에 따른 전달손실을 이용하여 음파 전달 조건의 변환점을 계산할 수가 있으며, 본 논문에서는 포물선 방정식 기반 음향모델을 이용하여 Pekeris 도파관에서 송‧수신기가 수층의 중심에 위치한 경우 전달손실을 모의한 후 변환점을 도출하였다. 계산된 변환점은 수층과 퇴적층의 음속비로 계산된 임계각으로 추정한 임계거리와 비교, 분석되었으며, 동일한 환경에서 수층에 음향채널이 존재하는 경우와 음원 수심 변화에 따른 변환점 변동성을 확인하였다. 최종적으로 2015년 5월, 제주도 서남쪽으로 약 65 km 떨어진 SAVEX15(Shallow Water Acoustic Variability EXperiment 2015) 실험에서 획득한 천해 환경에서의 거리에 따른 저‧중주파수 음파 전달 실험의 전달손실 자료를 이용하여 실험 해역에서의 음파 전달 조건 변환점을 도출하였으며, 이를 실험해역의 해양환경과 비교를 통하여 음전달 특성을 파악하였다.

키워드
음파전달
전달손실
변환점
구형 분산
원통형 분산
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Information
  • Publisher :The Acoustical Society of Korea
  • Publisher(Ko) :한국음향학회
  • Journal Title :The Journal of the Acoustical Society of Korea
  • Journal Title(Ko) :한국음향학회지
  • Volume : 37
  • No :1
  • Pages :1-11
  • Received Date : 2017-11-21
  • Revised Date : 2018-01-03
  • Accepted Date : 2018-01-30
  • DOI :https://doi.org/10.7776/ASK.2018.37.1.001
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